荣成人工湿地净化效果的季节和年际变化

Seasonal and annual variations of wastewater purification efficiency of Rongcheng constructed wetlands.

荣成人工湿地污水处理系统占地面积80 hm2,处理规模2.0万m3.d-1,1998年10月开始投入运行。对1999年1月到2004年12月荣成人工湿地污水处理系统净化效果以及净化效果的季节和年际变化进行分析。结果表明,人工湿地对SS、BOD5、CODC r均有很好的去除效果,出水浓度分别为(27.6±6.6)、(22.7±4.3)和(90.0±12.5)mg.L-1,去除率分别为73.9%、72.5%和63.8%。大肠菌群、粪大肠菌群去除率分别为99.7%和99.6%。对NH4+-N和TP去除效果较差,出水浓度分别为(11.2±2.7)和(2.03±0.29)mg.L-1,去除率分别为45.1%和30.2%。BOD5、CODC r、NH4+-N和TP的去除效果与季节变化有一定关系,NH4+-N受季节变化的影响最大,其次是TP,BOD5和CODC r受季节变化的影响相对较小。分析BOD5、CODC r、NH4+-N和TP去除效果的年际变化发现,BOD5、CODC r和NH4+-N去除率有增加的趋势。TP去除率在2001年和2002年基本相同,从2003年开始下降。

A full-scale wetland, 80 hm^2 in area, was constructed and put into operation in October 1998 in Rongcheng City,Shandong Province for treatment of wastewater. The treatment capability of the system was 2.0 × 10^4 m^3 · d^-1. To evaluate pollutants removal efficiency, and seasonal and annual variations of the system, water samples were collected and analyzed from January 1999 to December 2004. The results show that the constructed wetland could effectively reduce concentration of suspended solids by 73.9% ,BOD5 by 72.5% ,CODCr by 63.8% ,coliform by 99.7% and fecal coliform by 99.6%. The nitrogen removal efficiency （ 45.1% ） was relatively low, and the phosphorous removal efficiency （ 30.2% ） the least. BOD5, CODCr, NH4^＋ -N and TP removal displayed seasonal variations. NH4^＋ -N reduction varied more dramatically with the seasons in comparison with other parameters. The CODCr and BOD5 and NH4^＋ -N reduction efficiency showed a rising trend from 1999 to 2004. The TP reduction efficiency remained almost unchanged in 2001 and 2002 ,but began to decrease in 2003.